Gymnosperms (non-flowering plants) like pine, cedar, spruce etc. are better suited for creating xylem filters in comparison to angiosperms (flowering plants). This is because the length of the conduits in such plants is shorter, which allows for the creation of compact filters. In addition, the fraction of trunk or branch cross-section containing xylem is higher in gymnosperms, which provides greater membrane area. It is important to review the toxicity information of trees before creating these filters. For further guidance, please refer to the design guide in our ‘Filter manufacturing resources’ tab.